Card Network

What Is a Card Network?

A card network (also called a payment network or card scheme) is the company that provides the technology, rules, and routing infrastructure that makes electronic card payments possible. When a consumer taps a credit card at a store or enters card details online, the card network is the system that carries the authorization request from the merchant to the cardholder's bank and delivers the approval back in milliseconds.

The four major global card networks are Visa, Mastercard, American Express, and Discover. Regional networks also play significant roles: UnionPay dominates in China, RuPay in India, and Cartes Bancaires in France. Despite this variety, Visa and Mastercard jointly handle roughly 85% of global card payment volume outside of China, with over 8.4 billion cards in circulation accepted at 175 million merchant locations worldwide.

Critically, Visa and Mastercard do not issue cards or lend money. They are technology and standards companies that sit at the center of a four-party ecosystem, earning scheme fees on every transaction that flows through their rails.

How It Works

Understanding card networks requires understanding the four-party model that governs most card transactions globally.

The Four-Party Model

Every card transaction involves four distinct participants:

• Cardholder: the consumer who holds a payment card issued by their bank
• Merchant: the business accepting card payments
• Issuer: the bank that issued the card to the consumer, extends credit or manages the debit account, and bears the risk of nonpayment
• Acquirer: the bank or processor that provides the merchant with payment acceptance tools and manages settlement into the merchant's account

The card network connects issuers and acquirers, ensuring that a Visa card issued by any bank in any country works at any merchant that accepts Visa. This interoperability is the network's core value.

Transaction Flow

A typical card payment follows this path through the authorization and capture cycle:

1. The cardholder presents their card at the merchant (tap, chip insert, or online entry)
2. The merchant's terminal or payment gateway sends the transaction data to the acquirer
3. The acquirer routes the authorization request through the card network to the issuer
4. The issuer verifies the account, checks for sufficient funds or credit, runs fraud checks, and returns an approval or decline
5. The response flows back through the network to the acquirer, then to the merchant terminal
6. At the end of the business day, the merchant submits a batch of authorized transactions for clearing
7. The network facilitates settlement: the issuer transfers funds (minus interchange fees) to the acquirer, which deposits funds (minus the merchant discount rate) into the merchant's account

Authorization typically takes 1 to 3 seconds. Settlement, depending on the network and region, follows within one to two business days as part of the standard payment settlement cycle.

Open-Loop vs. Closed-Loop Networks

Card networks fall into two architectural models that differ in who controls each side of the transaction:

Open-loop networks achieve massive scale because any bank can join as an issuer or acquirer. This creates powerful two-sided network effects: more cardholders attract more merchants, which attract more cardholders. Closed-loop networks sacrifice scale for control, giving them richer data and tighter customer relationships. American Express leverages this to target higher spenders, with an average transaction value of roughly $150 compared to about $50 for Visa.

Network Economics

The fees merchants pay on every card transaction flow through a layered structure. For a deeper analysis, see our card network economics research article.

The Three Fee Layers

• Interchange fees: the largest component (typically 1.3 to 3.5% in the US), paid by the acquirer to the issuer. The card network sets the rates but does not keep this fee. Interchange compensates issuers for credit risk, fraud prevention, and rewards programs.
• Scheme fees (network assessment fees): the fee the card network itself earns, typically around 0.13 to 0.15% of transaction value for domestic transactions. Cross-border transactions carry premium fees.
• Acquirer markup: the fee the acquirer charges the merchant for payment processing services, bundled into the overall merchant discount rate.

Several jurisdictions regulate interchange. The European Union caps interchange at 0.2% for debit and 0.3% for credit cards. The US Durbin Amendment caps debit interchange for large banks. In unregulated markets, interchange remains the primary revenue driver for card issuers and the largest cost component for merchants.

Why Card Networks Are Highly Profitable

Card networks operate asset-light businesses with extraordinary margins. Visa's five-year average operating margin is roughly 67%, and Mastercard's is about 57%. They do not take credit risk (issuers do), do not hold deposits, and do not manage merchant accounts (acquirers do). They earn a fraction of a percent on every transaction, but that fraction applies to trillions of dollars in annual volume: Visa processed approximately $14 trillion in payments across 258 billion transactions in fiscal year 2025.

Use Cases

Consumer Payments

The most visible use case is everyday consumer spending. Card networks enable in-store, online, and mobile payments with near-universal acceptance. Consumer protections like chargebacks and zero-liability fraud policies are built into the network rules, providing a layer of trust that alternative payment methods must replicate.

Cross-Border Commerce

Card networks provide one of the simplest ways to make cross-border payments. A consumer in Japan can pay a merchant in Germany using the same card they use domestically, with the network handling currency conversion, compliance routing, and settlement across jurisdictions. This contrasts with the complexity of correspondent banking or SWIFT transfers for moving money internationally.

Digital and Embedded Payments

Card networks power the tokenized payment credentials behind Apple Pay, Google Pay, and in-app purchases. Over 50% of Visa transactions were tokenized in fiscal year 2025, with tokens replacing raw card numbers to reduce fraud. This infrastructure also enables embedded finance use cases where non-financial platforms offer payment functionality through card network rails.

Card Networks and Crypto

Rather than viewing blockchain-based payment systems as purely competitive threats, the major card networks are actively integrating stablecoin and crypto capabilities into their infrastructure.

Visa launched stablecoin settlement in the United States in December 2025, allowing partner banks to settle transactions in USDC over the Solana blockchain. By April 2026, Visa had expanded to nine supported blockchains and reported an annualized stablecoin settlement run rate of $7 billion, with over 130 stablecoin-linked card programs active across 50+ countries. Visa also partnered with Bridge (acquired by Stripe) to let cardholders spend stablecoin balances at any Visa-accepting merchant.

Mastercard has taken a parallel approach, partnering with Circle to enable USDC and EURC settlement for acquirers, and building its Multi-Token Network (MTN) for regulated blockchain transactions between banks. Both networks are positioning themselves as multi-rail platforms that can route payments across cards, real-time bank transfers, and blockchain rails. For a broader look at how crypto intersects with traditional payment rails, see our research on the crypto on/off-ramp landscape.

This convergence matters for projects like Spark. As card networks add stablecoin settlement capabilities, the boundary between traditional card payments and crypto-native payment layers blurs: a merchant accepting Visa may ultimately settle in stablecoins over blockchain infrastructure without changing their checkout experience.

Risks and Considerations

Concentration and Pricing Power

The duopoly of Visa and Mastercard gives these networks significant pricing leverage. Merchants have limited ability to refuse card acceptance because consumers expect it, creating an asymmetric bargaining dynamic. Network assessment fees have been increasing steadily, with new fee categories added regularly. Regulatory scrutiny of card network fees continues to intensify in the US, EU, and other markets.

Emerging Competitors

Account-to-account (A2A) payments bypass card networks entirely, routing funds directly between bank accounts over real-time payment rails. A2A payments are projected to reach $5.7 trillion by 2029. Systems like India's UPI, Brazil's Pix, and Europe's SEPA Instant demonstrate that real-time A2A can capture dominant market share in specific markets. However, A2A systems currently lack the built-in consumer protections (chargebacks, fraud liability) that card networks provide.

For a detailed comparison of these emerging rails, see our real-time payments research article.

Security and Compliance Burden

Participating in card networks requires compliance with PCI-DSS standards, 3-D Secure authentication protocols, and extensive transaction monitoring requirements. These standards protect consumers but create significant operational costs for merchants and payment processors, particularly smaller businesses.

This glossary entry is for informational purposes only and does not constitute financial or investment advice. Always do your own research before using any protocol or technology.